(Joseph Boudreaux with his home-grown mirliton variety)

Part of the inspiration for forming Mirliton.Org was the impact of Hurricane Katrina on New Orleans the the Louisiana coastal parishes. Mirliton plants will die if the roots are submerged in water for more than 48 hours: The Katrina flood destroyed all the vines in flooded areas in New Orleans and some coastal parishes.

To renew the tradition of backyard mirliton growing, we had to find traditional heirloom mirliton varieties grown outside New Orleans.  The mirlitons sold commercially in grocery stores (as Chayote) could not be used as seed: they are largely imported from high altitude sites in Costa Rica and Mexico and although they will sprout and grow a few stems, like many high-altitude plants, they normally succumb to our  unique growing environment and plant diseases.

Since 2007, we have searched for growers of what we call traditional “Louisiana heirloom mirlitons” by advertising in the Louisiana Department of Agriculture publication “Market Bulletin” and contacting Parish (county) Agricultural Extension Service staff–thanks to the assistance of the Louisiana State University extension service.  We also simply drove the roads along the bayous where mirlitons were traditionally grown on bayou banks (that’s how we found the Mister Rock mirliton variety).

We eventually found growers who had been growing the same variety for decades, although they are few and far between and a disappearing breed.  With the discovery of these growers–most of them older gardeners in their eighties who were upholding a family tradition of mirliton growing, we knew now that the traditional locally-grown varieties would once again thrive in New Orleans and rest of the state.

These growers would donate seed mirlitons to re-seed New Orleans and, as the demand grew, we would also buy from growers and give away the seed as sprouts and plants.  As word spread of our project (which began under the name “Adopt-A–Mirliton”), we ended up distributing seed throughout Louisiana, Texas, Mississipi, and Alabama.  We decided to feature some of the success stories on this blog from time to time.

In 2010 a reader of the Market Bulletin called me and said he knew of a grower in Broussard, Louisiana who had several vines of the same variety that he had been growing for decades.  I visited Joseph Boudreaux in Broussard and he donated a few of his mirlitons and I purchased several more.  Later, after an early freeze, he donated a few dozen freeze-damaged fruit that he assured us would germinate and grow: he was right.

We always name the variety after the person we first found growing it so that we can track the variety’s  progress as we distribute it throughout the region; heirloom varieties have different qualities that we are testing for, such as fruiting habits and disease resistance.  Naming the variety also allows us to find new growers who will “adopt” a specific variety and commit to growing it so that we will always have a reliable seed source and can preserve the genetic diversity of the locally grown varieties.

In 2011, Mirliton.Org donated three container plants of the Joseph Boudreaux variety to Sun Harvest Garden in New Orleans on Oretha Castle Haley Boulevard.  A small Central City community garden built on a cleared lot, Sun Harvest is run by Pam Broom, a long-time community activist and urban farming advocate.  Planted in the spring of 2011, the vine produced a small crop later that fall.  During the warm winter of 2012 (we never got a frost in central New Orleans), Pam harvested even more fruit and the plant is still producing during the traditional spring crop cycle.

Pam has distributed some of the the new fruit as seed to other gardeners in the area and her vine is, as mirlitons are inclined to do, rapidly taking over more of her garden.  But she’s happy with the prolific new arrival.  “One of the things that inspires me most about receiving mirliton plants from Mr. Joseph Boudreaux,” says Pam, “is that thanks to him, I am experiencing growing a beautiful, sweet and delicious variety in the heart of the City of New Orleans.”

From Broussard to New Orleans: mirlitons are making a comeback thanks to people who appreciate this iconic Louisiana plant.

Pam Broom with her Joseph Boudreaux mirliton variety vine at the Sun Harvest Garden in New Orleans

Lance Hill

Mirliton.org

The hot and rainy weather has brought out the annual anthracnose disease for mirlitons.  See the last summer’s blog entry here on this disease (I have added a photograph and link to more photos) which discusses how to recognize the different signs of powdery mildew and anthracnose. The growers guide on the web site has additional information.  Anthracnose infects almost all mirliton plants, especially in their first year, but depending on proper care and hopefully a low rate of evening rain showers, the disease will only affect a few stems and when those die, new stems will return.

Mirliton leaf infected with anthracnose plant disease. Note different browning pattern and the distinctive “shot hole” in the middle of the brown tissue, which does not occur with powdery mildew (anthracnose, unlike powdery mildew, can live on dead plant tissue and literally “eat a hole” through the plant)

I just posted to our FAQ page a comprehensive article on powdery mildew in Mirlitons.  I tried to get it to fit on the blog but apparently blogs are for concise thinkers–that rules me out.  Visit the FAQ page and Garden Blog for new useful information.

Lance Hill, Mirliton.Org

Ishreal Thibodeaux Variety Mirliton.  This is the only pure-white mirliton that we know of in the South.

Because of the warm winter, we have been getting an early crop of mirlitons that started in February.  I noticed these gelatinous clear growths on the immature fruit and then spotted an immature and mature leaf footed bug (stink bug) that feed on the fruit.

Fruit fluids (cytoplasm) leaking from fruit and jelling. Note flower and fruit are dead

Dr. Dale Pollet of LSU identified these growths as the cytoplasm (fruit fluids) oozing from the fruit after the leaf footed bugs have penetrated the fruit skin to feed on it.  In this case, attacking the very small immature fruit kills the fruit.  I have seen the insect also try to feed on mature fruit which does not display any immediate damage but will manifest as brown bruising after the fruit is picked.  They also spread plant diseases. The best method of control is to pick the insects off by hand, but they can be treated with organic fungicides.  If you use an organic pesticide, be careful that it is not toxic to bees (it is pollination season) and that it is not phytotoxic (can damage leaves in high temperatures).  Test it on a few leaves for one week first.

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Immature Leaf footed Bug on Mirliton Leaf

Leaf footed bug feeding on flowers. They can block pollination tubes.

Mature Leaf Footed Bug (stink bug)

Lance Hill

Mirliton.org

Lance@mirliton.org

September 23rd will be the autumn equinox which means that in about 10 days we will have equal daylight and darkness.  Since mirlitons (chayote) are photoperiodic (flowering triggered by equal light), we should start to see some flowering soon.  Mirlitons are also thermoperiodic which means a little cool weather will also stimulate flowering.  Here are a few things to keep in mind for the fall crop:

1. Don’t fertilize during this period.  Mirlitons require additional nitrogen when they first start and throughout the vining stage, but they produce more fruit in the fall if they have less available nitrogen.  This is always one of the tricky things about mirlitons–they have different nitrogen requirements at different times.  This is a challenge for growers using manure since it is slow release, but the slow release fertilizers, natural or synthetic, are a good way to avoid excessive nitrogen.

2. Watch for leaf footed bugs ( a variety of stink bugs).  There are photos of them on the web page photo site.  Immature leaf footed bugs are red and easy to identify.  I have seen that they will feed on flowers and fruit–leaving the fruit with late bruising and a bitter taste.  They are easily treated with organic pesticides or just manually picked off.  Various beetles can cause damage to leaves and stems and introduce wilt and other diseases and they can also be treated.  In many ways, the traditional overhead trellis makes it difficult to detect and treat insects, so there is an argument for a lower trellis. In addition, a 4-5 foot trellis permits for easier hand-pollination and the trellis can be more easily covered with plastic to protect from cold temperatures.

3. When is a mirliton ripe?  Most fruit will mature within 21 days of flower germination, and the “thumbnail test” is the easiest way to test for maturity. Simply press youth thumbnail into the flesh and if it dents the flesh easily, the fruit is immature and still contains too much moisture and not enough structure.  I  mature mirliton will be hard and resist denting. Some growers like larger mirlitons (the average at picking, depending on the variety, is 8-12 ounces).  You can leave the fruit on the vine for several weeks and some heirloom varieties will get very large–up to 30 ounces.  Other varieties have a terminal fruit growth of about 10 ounces.  The older the mirliton, the more fibrous the flesh.  Again, it is a matter of taste and you can experiment with picking and boiling at different sizes.

5. Pollination. Bees are the primary pollinators  for mirlitons.  Bees are finicky and systematic feeders and simply having them in your garden does not mean they will pollinate your plant.  Go out about 10:00 a.m. on a sunny day and see if they are visiting your mirliton flowers.  If they are not, you have to hand-pollinate per the instructions on the photo site or you can spray with Fruit Boost or other artificial queen bee hormones.  Only one pollination is necessary since the pollen is sticky and adheres to the female stigma.  Mirlitons will flower from October through December if the weather is warm, but hormone levels drop off after November so germination rates are lower.

6. Protect from cold weather.  You can take your chances with cold weather, but immature fruit will die when temperatures drop below 55 degrees F.  If you want your mirlitons to survive cool weather damage or frost damage, invest in a large roll of plastic, a drop light, and a receptacle thermostat (see growers guide).  By covering your vine and keeping the temperature above 60 degrees, you will protect the new fruit and be able to harvest all the way through December.  You may have to removed the plastic during the day to prevent overheating. Freeze damaged fruit cannot be eaten but they do grow well as seeds if they are planted immediately on containers or mounds.

7. In the growers guide, we suggest several methods of overwintering sprouts.  Leo Jones of  Marrero, Louisiana told me of good technique of overwintering sprouts if you don’t have container room.  He digs a hole in the garden and fill it with straw and places several mirlitons in the hole and covers with soil and mulches. He digs these up in march and they have developed a good root structure and shoot and can be transplanted to mounds (bury the roots and shoot completely to avoid sun scorching.   If you are going to store mirlitons in paper bags (the old fashioned way, which we don’t recommend), follow the instructions in the growers and powder the fruit in sulfur to protect them from fungi.

8. As always, send us photos of your plants.  We are always looking for different heirloom varieties, so feel free to email us about growers in your area.   This last summer we had an anthracnose epidemic which damaged many of the vines in the Southern part of the state, but rest of the state had low rainfall so we expect a good crop of heirloom mirliton seeds.  If you are subscribed to the “Alerts” on the web site, you will be notified when seed is available through cooperating garden centers or directly from growers.   It is always advisable to start with 3-5 sprouts to increase your chances of getting a plant through the first year, which is the key to a healthy and productive vine.  Second-year plants have better root structure and “systemic acquired resistance” means that plants exposed to fungal toxins like anthracnose will develop some natural resistance to the fungus in future years.

Lance Hill

Mirliton.org

Lance@mirliton.org

The recent deluge of rain in South Louisiana has certainly underscored the need for what I call “single event gardening.”  What this means is that in ordinary weather conditions and plant disease and pest environments, we can simply plant a mirliton (chayote, Sechium edule) and it will take care of itself.  But if we want the plant to thrive and survive as a perennial for several years, we need to plan ahead and make provisions for events that may never occur, but if they do, they will certainly reduce fruit production or even kill the plant.  Excessive rain is one of those “single events” and right now all over New Orleans, the only city in the United States where we have to garden below sea level and where there is very little natural sub-surface drainage,  vegetable gardens are struggling to maintain sufficient air pore space to ensure plant functions.  For those who planned ahead, the 3-5 inches of rain a day pose no problem.

When soil is water saturated and no oxygen is available for roots — or for gas exchange–plants go through dramatic changes to survive.  They are literally in “anoxic” soil like the dead zones in the Gulf of Mexico.  They shift from aerobic metabolism to anaerobic metabolism: they have only 5% of the energy efficiency they have in healthy aerated soil; they produce toxic organic and inorganic compounds and they deprive the leaves of potassium crucial to maintaining leaf functions.  After 24-48 hours, not only have the roots been damaged making it more difficult for them to uptake water and nutrients; and leaf functions have been weakened and the whole plant is vulnerable to disease.  The result can be that even after the rains have subsided, a perfectly healthy looking plant under heat stress suddenly wilts, turns brown and dies to the root.

The solution is very simple.  You need two things: a fast-draining, well-aerated growing medium (comparable to high-quality commercial potting mix) and you need to elevate your soil so that the only exit route for excess water is not the saturated ground soil which cannot absorb any more water.  This means either a planting hill system using 4-6 cubic feet fast-draining mix or a raised bed that has at least a 5 inch gravel base and 18-24 inches of good-draining soil.  Installing a french drain pipe inside the raised bed is also suggested.  All these methods are demonstrated on the photo section in “mirliton 101” on our web site at www.mirliton.org and covered in the two growers guides.

Plant disease this year was compounded by the long, dry, hot spring which was conducive to powdery mildew (Podosphaera xanthii), a particularly dangerous fungus comprised of at least 28 “races”.  Although is not as prevalent as other plant diseases that afflict mirlitons, it can be deadly since most of our locally-grown heirlooms are not resistant to this air-borne fungus.  Fortunately, powdery mildew (PM) can be eradicated by the natural fungicide potassium bicarbonate (pb).  Click here to see photo album on PM and recommendations on using potassium bicarbonate.

The big headache this summer is the plant disease anthracnose caused by the a fungus named Colletotrichum lagenarium. It is a chronic problem with mirlitons and it is the main reason plants die the first year.  It is relatively easy to distinguish anthracnose disease from powdery mildew (PM) since it is a soil-borne fungus and normally splashes up on the bottom leaves and travels from leaf-leaf in a linear fashion.  While both PM and anthracnose start with similar symptoms (yellow splotches on green leaves), anthracnose is a more versatile fungus–the scientific terms for its mode of parasitic activity are biotrophic, saprotrophic, and necrotrophic–which simply means it can live off live tissue or dead tissue.

This means the fungal pathogen will destroy a section of the leaf turning it yellow, then consume the remaining section until it is brown (necrotic) and it will quite literally eat a hole through the plant.  The brown hole in the leaf or on the edges is an easy way to diagnose anthracnose. PM, in contrast, is an air-borne spore that can deposit at the top of a plant and is not as versatile; normally the leaf will simply uniformly turn yellow and wilt before dead (necrotic) paper-like spots with holes appear.  It is always best to send a leaf sample to your local extension office for a definitive diagnosis, but the photo section of our web site offers several free ways to make a tentative diagnosis.

Mirliton leaf infected with anthracnose.  This is a good example of the signs of anthracnose.  The fungus starts on living tissue but also has the ability to extract nutrients from dead tissue.  Note distinctive anthracnose “shot hole” in middle of now dead tissue where fungus has fed on dead tissue–unlike powdery mildew. Wedge-shaped yellowing or brown (dead) patterns starting at the leaf edges also distinguish anthracnose from powdery mildew. Anthracnose travels through plant cells so tends to follow leaf vein design. Powdery mildew spreads on the surface of leaves, so there is less conformity to leaf vein structure (initial yellow splotches overlap veins) and more generalized yellowing of entire leaf and browning/wiling of entire leaf simultaneously.

Normally when anthracnose infects the leaves,  petioles, and stems, it will eventually split the stem and that will prevent the flow of nutrients to the ends of the stem.  But for every stem lost, a healthy plant in well-drained soil will send up a new shoot.  So for the first year it is a tug-of war with the disease but generally the disease will abate in August. Click here to see more photos of infected leaves (click on photos to enlarge).

One important discovery we made this year is that the light-brown  “bark” that forms at the crown of the plant is a lignocellulose covering (lignin and cellulose strengthen woody plants) which the anthracnose hyphae “germ tube” cannot penetrate.  This protects the base of the plant from the fungus and almost all new growth will originate close to or below this bark.  It is important not to cover this protective bark with applications of compost, mulch, or manure since it may weaken the bark (manure can always be spread at least 6 inches from the base since roots will eventually extend up to 6 feet in all directions).

Currently, there are no scientific tests on organic fungicides to treat anthracnose, but there are some biological and soft-chemical treatments that have been tested on other related plants. But keep in mind that mirlitons are unique and the effect of treatments on tendril action is important, since tendril growth (anchoring to the trellis) appears to stimulate meristem growth (shoot tip growth).  For now, the best protection against anthracnose is (1) use only locally grown heirloom mirlitons for seed since they probably have more resistance to the disease (otherwise they would not have survived for decades in our region); (2) plant in well-drained,  aerated sites; (3) provide plenty of trellis space so leaves can spread out and get maximum exposure to sun (a natural fungicide) and air circulation;  (4) use a horizontal trellis where possible to avoid leaf crowding; and (5) use sanitary practices so as not to transfer anthracnose spores from one leaf to another (watch where you put your hands and disinfect tools).  Once leaves and stems are brown and dead, remove them and dispose away from the mirliton.  Anthracnose creates spore-producing “ascocarps” that contain spores and can live in the soil for up to a year.

Finally, play the odds and always plant multiple plants.   Raising one mirliton is tricky, but raising several increases the odds that you will make it through the first year.  If you treat the soil for root-knot-nematodes (see the guide) and protect the plant from root freeze, each year the plant will become more resistant to anthracnose–more capable of producing new shoots to compensate for damaged shoots.

These are all “single event gardening” guidelines.  You can just plant the mirliton and it is possible that none of these environmental or disease problems may occur and your plant will do well.  On the other hand, if you take precautions, the health of your mirliton is secured. Given that mirlitons become more resistant to disease as they mature, and given that fruit production doubles every year if maximum root-space and trellis-space is provided (from 40 fruit, to 80, to 160, t0 350),  the protections to ensure a multi-year plant are worth the time and effort. Lance Hill Mirliton.org Lance@mirliton.org

I talked to someone the other day who had purchased a mirliton plant from a local nursery and it was not growing well.  When I asked him to find out where the nursery obtained the seed, it turned out they had bought them from Wal-Mart.  Most of the mirlitons (chayote, Sechium edule) sold in groceries are imported from Costa Rica where they are grown at altitudes of over 3,500 feet.   My recent research into the USDA records indicate that as far back as 1920, the USDA’s experimental station in Brooksville, Florida had discovered that this high-altitude variety will not grow in our hotter, heavy-rain Gulf Coast climate.   Those findings were published in 1947 in a Botany Journal. Field research by Dr. Moha Dutta Sharma at the IAAS in Nepal in the 1990s found genetic variety in mirlitons–some were more suceptible to disease and fungus than others–and some flowered only male flowers when transplanted into different climates.  DNA research in the last ten years has scientifically established that there are clear genetic differences among domestically cultivated mirlitons in Latin America. I am not arguing that a determined gardener can’t get these store-bought varieties to grow, but these mirlitons are intended for consumption, not garden seed.   Moreover, if a grower manages to get an imported variety to grow, it can potentially cross-pollinate with our few remaining heirloom mirlitons and reduce our home-grown line’s disease resistance or yield. There are only two ways to determine if you are purchasing an heirloom mirliton–one that has been successfully grown for decades in Louisiana without the use of pesticides and fungicides.  First, you can obtain seed from us at mirliton.org.  We research varieties, interview growers, and do site visits on farms to determine if plants are grown naturally.  Unfortunately because of the crop disaster we had last year (late flowering and early cold temperatures destroyed most of the heirloom crop), we do not have any seed to distribute. While our seed distribution is free, we do expect next fall that our growing network of heirloom growers will produce thousands of seeds and they will be available for sale at nurseries that we certify as only selling home-grown Louisiana mirlitons. The second way to determine if a mirliton plant/sprout is an authentic Louisiana heirloom is to find a grower who has grown the same variety for years.  Commercial imported varieties sold in stores did not enter our markets until about 20 years ago.  There are still growers in South Louisiana who are growing varieties that are more than 20 years in production, so they clearly were introduced before the Costa Rican chayotes became available. So consumer beware!  Anyone can get a store-bought imported mirliton to sprout in a container and grow a few feet.  Unfortunately, the consumer will be on the short-end of the stick and ultimately our traditional home-grown varieties will be placed at risk.

Lance Hill Mirliton.org Lance@mirliton.org